In the games

She is the Frontier Brain of the Battle Arcade in the Sinnoh and Johto regions. Fantina is a fan of Dahlia's dancing style. An NPC inside of the Battle Arcade notes that Dahlia has a peculiar fashion sense. Dahlia will challenge the player on the 21st consecutive battle and award them the Battle Arcade's Silver Print if defeated. She returns when the player reaches the 49th battle, this time awarding the Gold Print when beaten.

Quotes

Initial battle

Before battle

"No need to worry. ♪ Let chance do what it does. Like surprises from the game board, life goes through twists and turns. No need to worry. ♪ Things will go as they will. But, enough of that. I know one thing for certain. You have arrived here not merely because you were lucky. Let us not waste any time. I wish to test your skills myself!"

After the roulette

"Always be smiling! Luck comes to those who are happy! That's why I always keep a big smile and believe in my Pokémon when I battle."

Being defeated

"You're so very, very good! My Pokémon had a good time, too!"

After being defeated

"How fabulous of you! Your love of Pokémon shone through, and, in turn, your Pokémon believed in you. That is why you handled everything thrown your way splendidly. A most wonderful victory it was!"

Rematch

Before battle

"No need to worry. ♪ Let chance do what it does. Like surprises from the game board, life goes through twists and turns. No need to worry. ♪ Things will go as they will. But, enough of that. You are proving yourself incredible. Are you incredible because you are so lucky you shrug off bad luck entirely? Or, are you so incredibly talented to not be swayed by luck, good or bad? I wish to see for myself what brought you to me today!"

After the roulette

"Whenever I battle someone tough, I smile. I cannot help it! How about you? What do you do? Do you laugh? Cry? Get angry?"

"Truly, it was so very fabulous of all of you! Bad luck, you cast aside, and good luck, you netted. That you did so is evidence of your abilities. By defeating me, Dahlia, you have proven your mastery brilliantly! I am sincerely happy for having this battle against you!"

Dahlia first appears along with her fellow Frontier Brains, Palmer, Thorton, and Argenta in a meeting; afterward they go back to their facilities. Dahlia later appears at her facility, the Battle Arcade, when Platinum racks up enough wins that will allow her to challenge the Frontier Brain soon. After Platinum wins enough times, she becomes eligible to fight Dahlia. Due to an unexpected earthquake, Platinum is unable to stop the roulette in time and Dahlia does so instead, causing it to land on the Pokémon swap button.

Due to it landing on that button, Dahlia and Platinum switch their teams and begin battling. At first, Dahlia has the upper hand because of Platinum's refusal of harming her own Pokémon but, once she gains the resolve to do so, she manages to defeat the Arcade Star. Later, Dahlia helps Platinum with her research of the Distortion World and despite her "Que Sera, Sera" attitude, she throws a tantrum offscreen due to her loss to Platinum being her first one.

Pokémon

On hand

Ludicolo

Dahlia's Ludicolo was used to battle Platinum at the Battle Arcade. However, due to the rules of the Pokémon swap button, it was sent to battle on Platinum's side. It managed to deal heavy damage to Platinum's Rapidash. After that, it was returned to Dahlia.

Dahlia's Medicham was used to battle Platinum at the Battle Arcade. However, due to the rules of the Pokémon swap button, it was sent to battle on Platinum's side. Medicham was used to defeat Platinum's Rapidash, causing Dahlia to lose the match. After that, it was returned to Dahlia.

Dahlia's Togekiss was used to battle Platinum at the Battle Arcade. However, due to the rules of the Pokémon swap button, it was sent to battle on Platinum's side. In the battle, it was defeated by a single Focus Blast from Lopunny. After that, it was returned to Dahlia.

In the TCG

Dahlia's PokémonCards listed with a blue background are only legal to use in the current Expanded format.Cards listed with a silver background are legal to use in both the current Standard and Expanded formats.